letra.a <- letters[rep(c(1),times=6)]
numeros <- rep(c(1,2,3), each=3)
decrescente <- c(rep(1,3),rep(2,2),3)
sequencia <- seq(from=1, to=5, length = 5)
impares <- c(seq(from=1, to=5, length = 5), seq(from=4, to=1))